Search for the role of eIF5A in endoplasmic reticulum stress using large-scale proteomic GFP screen

Abstract

The translation factor 5A (eIF5A) is highly conserved in Archaea and eukaryotes and is essential for cell viability. This is the only protein known to contain the amino acid residue hypusine, essential for eIF5A function, generated by a post-translational modification. Although it was initially suggested a function for eIF5A in the translation initiation, it was in the elongation step that eIF5A function was better demonstrated. Recent data from our group revealed a possible role for eIF5A in the secretory pathway and endoplasmic reticulum (ER) translocation, suggesting an involvement for eIF5A on the translation of specific mRNAs related to these pathways. In addition, it has been suggested an activation of the ER stress response upon eIF5A depletion in mammalian cells. Interestingly, our laboratory have some unpublished data demonstrating that yeast eIF5A mutants are sensitive to dithiothreitol (DTT) and resistant to tunicamycin, both drugs that activate the ER stress response upon. To better understand this dual behavior of eIF5A mutants, we propose here the use of the S. cerevisiae GFP collection for a proteomic screen upon induction of ER stress by DTT and tunicamycin. Therefore, the resulting protein abundance data will contribute to determine how eIF5A function correlates with the ER stress, and also to the general role of eIF5A during gene expression. (AU)